We examined the impact of maternal obsessive-compulsive disorder (OCD) on gestational age and birth weight of infants. The sample included 63 mothers (28 patient and 35 controls). OCD and other psychiatric diagnoses were determined with a structured clinical interview. Birth weight and gestational age were lower in the newborns exposed to maternal OCD compared to ones who were not exposed. The results suggest that maternal OCD may negatively affect fetal weight growth and gestational duration.